Heat Sink Package

ABSTRACT

Provided are a heat sink package in which a semiconductor package and a heat sink are bound to each other and a method of fabricating the same. 
     The heat sink package includes a heat sink having a cavity on an upper surface thereof; a metal layer formed on the bottom surface of the cavity; a solder paste layer formed on the metal layer; a substrate on the solder paste layer; and a lead and a semiconductor chip mounted on the substrate.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a divisional of U.S. patent application Ser. No12/358,758 filed Jan. 23, 2009 which claims the benefit of Korean PatentApplication No. 10-2008-0011058, filed on Feb. 4, 2008, in the KoreanIntellectual Property Office, the disclosures of which are incorporatedherein in their entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink package in which asemiconductor package and a heat sink are bound to each other and amethod of fabricating the same.

2. Description of the Related Art

Generally, a semiconductor package is prepared by mounting a single or aplurality of semiconductor chips on a chip pad in a lead frame, andsealing the chips using a molding member such as epoxy molding compound(EMC) to protect the inside of the semiconductor package, and thesemiconductor package is mounted on a printed circuit board (PCB)substrate. Recently, as electronic devices have increasingly been madewith high speed, large capacity and high integration, there is a need toachieve small sized, inexpensive and light weight power devices appliedto automobiles, industrial machinery and home appliances.

Power devices such as a silicon controlled rectifier (SCR), a powertransistor, an insulated-gate bipolar transistor (IGBT), a metal oxidesemiconductor (MOS) transistor, a power rectifier, a power regulator, aninverter, a converter, and a combination thereof are designed to operateat a voltage in the range of 30 to 1000 V or greater. Such power devicesare distinguished from conventional logic or memory devices that operateat a high voltage, and thus a semiconductor package for power devicesneeds to have superior heat discharging capability for discharging heatgenerated from the power devices and insulating properties for operatingat a high voltage.

Generally, in order to discharge heat generated from power devices, aheat sink is assembled on a semiconductor package as disclosed byFairchild Semiconductor Corporation in Korean Patent Application No.2007-20564.

FIG. 1 is an exploded perspective view of a conventional semiconductorpackage for power devices 10 and a heat sink 30.

Referring to FIG. 1, a heat sink 30 formed of a metallic material may beattached to a semiconductor package for power devices 10. The heat sink30 is assembled to a semiconductor package for power devices 10 by abolting member 20 that passes through a bolting hole 10 h of thesemiconductor package for power devices 10.

Typically, a resin-based material used for a transfer molding process,such as an epoxy molding compound (EMC) is used as a molding member 10 aforming the external shape of a semiconductor package for power devices.Since the semiconductor package for power devices 10 can be simply andeconomically fabricated using such a resin-based material, theresin-based material is applied to various fields. However, when theheat sink 30 and the semiconductor package for power devices 10 areassembled by the bolting member 20, cracks and warpages may be inducedin the molding member 10 a due to compressive stress and shear stressapplied to the surface of the semiconductor package for power devices 10by the bolts.

Such cracks and warpages may provide a moisture absorbing passage in thesemiconductor package for power devices 10 or destroy insulation so thatreliability or lifetime of the power devices may be decreased.

In addition, an insulation sheet and/or a thermal grease is generallyinterposed between the semiconductor package for power devices 10 andthe heat sink 30. However, the insulation sheet and/or the thermalgrease may increase thermal resistance so that reliability or lifetimeof the power devices may be decreased.

SUMMARY OF THE INVENTION

The present invention provides a heat sink package in which asemiconductor package and a heat sink are bound to each other in orderto prevent cracks and warpages and secure low thermal resistance.

According to an aspect of the present invention, there is provided aheat sink package. The heat sink package includes: a heat sink having acavity on an upper surface thereof; a metal layer formed on the bottomsurface of the cavity; a solder paste layer formed on the metal layer; asubstrate on the solder paste layer; and a lead and a semiconductor chipmounted on the substrate. The heat sink may comprise aluminum and themetal layer may comprise copper. The substrate may be a direct bondedcopper (DBC) substrate, a thick or thin film copper (TFC) substrate or adirect fired copper (DFC) substrate. The metal layer, the solder pastelayer, the substrate and the semiconductor chip may be arranged in thecavity. The depth H of the cavity may be greater than the sum of aheight of the metal layer, a height of the solder paste layer, a heightof the substrate and a height of the semiconductor chip. The heat sinkpackage may further comprise an epoxy resin filling in the cavity inorder to protect the metal layer, the solder paste layer, the substrateand the semiconductor chip. The lead may extend from the substrateoutside of the epoxy resin.

According to another aspect of the present invention, there is providedanother heat sink package. The heat sink package includes: a heat sinkhaving a cavity on an upper surface thereof; a metal layer formed on thebottom surface of the cavity; a solder paste layer formed on the metallayer; and a semiconductor package on the solder paste layer. The heatsink may comprise aluminum and the metal layer comprises copper. Thesemiconductor package may comprise: a substrate; a lead and asemiconductor chip on the substrate; and a molding member sealing thesemiconductor chip on the substrate. The substrate may be selected fromthe group consisting of a direct bonded copper (DBC) substrate, a thickor thin film copper (TFC) substrate and a direct fired copper (DFC)substrate.

According to another aspect of the present invention, there is providedanother heat sink package. The heat sink package includes; a heat sink;a metal layer formed on the heat sink; a solder paste layer formed onthe metal layer; and a semiconductor package on the solder paste layer.A groove may be formed on the upper surface of the heat sink around thesolder paste layer in order to prevent overflow of the solder pastelayer. The semiconductor package may comprise: a substrate; a lead and asemiconductor chip on the substrate; and a molding member sealing thesemiconductor chip on the substrate. The lead may extend from thesubstrate outside of the molding member. The substrate may be selectedfrom the group consisting of a direct bonded copper (DBC) substrate, athick or thin film copper (TFC) substrate and a direct fired copper(DFC) substrate.

According to another aspect of the present invention, there is providedanother heat sink package. The heat sink package includes: a heat sinkhaving a cavity on an upper surface thereof; an insulating anodizedlayer formed on the bottom surface of the cavity; a metal layer patternon the anodized layer; and a lead and a semiconductor chip mounted onthe metal layer. The heat sink may comprise aluminum and the anodizedlayer comprises Al₂O₃. The anodized layer, the metal layer pattern andthe semiconductor chip may be arranged in the cavity. The depth H of thecavity may be greater than the sum of a height of the anodized layer, aheight of the metal layer pattern, and a height of the semiconductorchip. The heat sink package may further include an epoxy resin fillingin the cavity in order to protect the anodized layer, the metal layerpattern and the semiconductor chip. The lead extends from the metallayer pattern outside of the epoxy resin.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is an exploded perspective view of a conventional semiconductorpackage for power devices and a heat sink;

FIG. 2 is a cross-sectional view of a heat ink package according to anembodiment of the present invention;

FIGS. 3A to 3E, 3G and 3H are cross-sectional views of the heat sinkpackage of FIG. 2, and FIG. 3F is a perspective view of the heat sinkpackage of FIG. 2;

FIG. 4 is a cross-sectional view of a heat sink package according toanother embodiment of the present invention;

FIGS. 5A, 5C to 5E are cross-sectional views of the heat sink package ofFIG. 4, and FIG. 5B is a perspective view of the heat sink package ofFIG. 4,

FIG. 6 is a cross-sectional view of a heat sink package according toanother embodiment of the present invention:

FIGS. 7A to 7C are cross-sectional views of the heat sink package ofFIG. 6 illustrating a method fabricating the heat sink package;

FIG. 8 is a cross-sectional view of a heat sink package according toanother embodiment of the present invention; and

FIGS. 9A, 9B and 9D are cross-sectional views of the heat sink packageof FIG. 8, and FIG. 9C is a perspective view of the heat sink package ofFIG. 8 illustrating a method fabricating the heat sink package.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. The present invention may, however, be embodied inmany different forms and should not be construed as limited to theexemplary embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Inthe drawings, thicknesses of layers and regions may be exaggerated forclarity.

Like reference numerals in the drawings denote like elements. It willalso be understood that when an element such as a layer, a region or asubstrate is referred to as being on another element, it can be directlyon the other element, or intervening elements may also be present.

Also, spatially relative terms, such as “above” or “upper” and “below”or “lower” and the like, may be used herein for ease of description todescribe the relationship of one element or feature to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation, in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “above” other elementsor features would then be oriented “below” the other elements orfeatures. Thus, the exemplary term “above” can encompass both anorientation of above and below.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It will be understood that, although the terms first, second, etc., maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish, one element, component, region, layer or section fromanother region, layer or section.

FIG. 2 is a cross-sectional view of a heat sink package according to anembodiment of the present invention.

Referring to FIG. 2, a heat sink package includes a heat sink 210 havinga cavity C on an upper surface thereof. A metal layer 220 is formed onthe bottom surface of the cavity C. The metal layer 220 may be formed onthe entire or a part of bottom surface of the cavity C.

The heat sink 210 may include aluminum. In this case, the metal layer220 may include copper. However, these materials forming the heat sink210 and the metal layer 220 are exemplarily described, and the scope ofthe present invention is not limited thereto. The copper layer may beformed, for example, by plating, but may also be formed by a chemicalvapor deposition.

A solder paste layer 230 is formed on the metal layer 220, Since thesolder paste layer 230 assembles the heat sink 210 and the substrate105, a bolt member which is conventionally required is not necessary.

A substrate 105 is attached to the solder paste layer 230. The substratemay be a direct bonded copper (DBC) substrate, a thick or thin filmcopper (TFC) substrate or a direct fired copper (DFC) substrate. FIG. 2illustrates a DBC substrate or TFC substrate. The DSC substrate or TFCsubstrate may include an insulating layer 102 formed of an insulatingmaterial, for example, a ceramic material an upper pattern 101 formed ofcopper and a lower pattern 103 formed of copper. The insulating layer102 included in the substrate 105 insulates semiconductor chips 130,140, 150 and/or 160 and the heat sink 210.

A lead 170 and at least one of the semiconductor chips 130, 140, 150and/or 160 are mounted on the substrate 105. The semiconductor chips130, 140, 150 and/or 160 may include a power control semiconductor chipand/or a low-power semiconductor chip driving the power controlsemiconductor chip. For example, the semiconductor chips 130, 140, 150and/or 160 may include a silicon-controlled rectifier (SCR), a powertransistor, an insulated-gate bipolar transistor (IGBT), a metal oxidesemiconductor (MOS) transistor, a power rectifier, a power regulator, aninverter, a converter, a manual device or a combination thereof. Thesemiconductor chips 130, 140, 150 and/or 160 are electrically connectedto the substrate 105 by a bonding wire (not shown).

Although a dual in-line package (DIP) having two rows of leads 170 isexemplarily illustrated in FIG. 2, the scope of the present invention isnot limited to the structure of the lead 170. For example, a singlein-line package (SIP) having a single row of the lead 170 may beapplied.

The depth H of the cavity C of the heat sink 210 may be greater than thesum of a height of the metal layer 220, a height of the solder pastelayer 230, a height of the substrate 105 and a height of thesemiconductor chip 130, 140, 150 or 160. Here, the metal layer 220, thesolder paste layer 230, the substrate 105 and the semiconductor chips130, 140, 150 and/or 160 are arranged in the cavity C and do notprotrude the upper surface of the heat sink 210.

Empty space of the cavity C may be filled with an epoxy resin 250 inorder to protect the metal layer 220, the solder paste layer 230, thesubstrate 105 and the semiconductor chips 130, 140, 150 and/or 160. Thelead 170 may extend from the substrate 105 outside of the epoxy resin250. Thus, only a part of the lead 170 can be sealed with the epoxyresin 250.

FIGS. 3A to 3E, 3G and 3H are cross-sectional views of the heat sinkpackage of FIG. 2, and FIG. 3F is a perspective view of the heat sinkpackage of FIG. 2.

First, referring to FIGS. 3A and 3B, a substrate 105 or 115 is prepared.

FIG. 3A illustrates a direct bonded copper (DBC) substrate or a thick orthin film copper (TFC) substrate. The DBC substrate or TFC substrate 105includes an insulating layer 102 formed of an insulating material, forexample, a ceramic material, an upper pattern 101 formed of copper and alower pattern 103 formed of copper.

FIG. 3B illustrates a direct fired copper (DFC) substrate. The DFCsubstrate 115 includes an insulating layer 112 formed of an insulatingmaterial, for example, a ceramic material, an upper pattern 111 formedof copper and a lower pattern 113 formed of copper. A bonding layer 114may be interposed between the insulating layer 112 and the upper pattern111, and between the insulating layer 112 and the lower pattern 113, Thebonding layer 114 may include Ag.

For descriptive convenience, hereinafter the DBC substrate or TFCsubstrate 105 will be exemplarily described. However, it may be replacedby the DFC substrate 115, and the scope of the present invention is notlimited to the type of the substrate.

Referring to FIG. 3C, a first solder paste layer 120 is formed on theDBC substrate or TFC substrate 105. The first solder paste layer 120 maybe formed using screen printing.

Referring to FIG. 3D, lead 170 and at least one of the semiconductorchips 130, 140, 150 and/or 160 are mounted on the DBC substrate or TFCsubstrate 105 through the medium of the first solder paste layer 120 toform a first structure 100. In FIG. 3D, the first solder paste layer,although it is not shown, may be interposed between the upper pattern101 and the lead 170 and between the upper pattern 101 and at least oneof semiconductor chips 130, 140, 150 and/or 160.

Referring to FIGS. 3E and 3F, a heat sink 210 having a cavity C on anupper surface thereof is prepared. A metal layer 220 is formed on thebottom surface of the cavity C. The metal layer 220 may be formed on theentire or a part of bottom surface of the cavity C. The heat sink 210may include aluminum. In this case, the metal layer 220 may includecopper. However, these materials forming the heat sink 210 and the metallayer 220 are exemplarily described, and the scope of the presentinvention is not limited thereto. The copper layer may be formed, forexample, by plating, but may also be formed by a chemical vapordeposition.

A second solder paste layer 230 is formed on the metal layer 220 to forma second structure 200. The second solder paste layer 230 may be formedon the metal layer 220 using dotting or screen printing. Since thesecond solder paste layer 230 assembles the heat sink 210 and thesubstrate 105, a bolt member which is conventionally required is notnecessary.

Referring to the cross-sectional view of the second structure 200 shownin FIG. 3E and the perspective view of the second structure 200 shown inFIG. 3F, the cavity C has a concave shape on the upper surface of theheat sink 210. However, the cavity is exemplarily illustrated. Thecavity C may have any configuration as long as the substrate 105 and thesemiconductor chips 130, 140, 150 and/or 160 constituting the firststructure 100 can be arranged in the cavity C and do not protrude theupper surface of the heat sink 210. For example, according to FIG. 3F,the cavity C in a length direction of the heat sink 210 are closed byside walls and the cavity in a width direction of the heat sink 210 areopen. However, all of the side walls of the cavity C may be closedaccording to another embodiment.

The depth H of the cavity C of the heat sink 210 may be greater than thesum of a height of the metal layer 220, a height of the second solderpaste layer 230, a height of the substrate 105 and a height of thesemiconductor chip 130, 140, 150 or 160.

Referring to FIG. 3G, the first structure 100 is mounted on the secondstructure 200. That is, the substrate is mounted on the heat sink bydirectly contact and bind the substrate of the first structure 100 andthe second solder paste layer of the second structure 200.

Referring to FIG. 3H, empty space of the cavity C may be filled with anepoxy resin 250 a in order to protect the metal layer 220, the solderpaste layer 230, the substrate 105 and the semiconductor chips 130, 140,150 and/or 160. FIG. 3H illustrates a process of filling the cavity Cwith an epoxy resin 250 a. The epoxy resin 250 e may be filled in thecavity C using a potting method. After the cavity C is filled with theepoxy resin 250, a curing process is performed. Subsequently, electricaltests are performed to determine the performance of products,

FIG. 4 is a cross-sectional view of a heat sink package according toanother embodiment of the present invention.

Referring to FIG. 4, a heat sink package includes a heat sink 310 havinga cavity on an upper surface thereof. An insulating anodized layer 320is formed on the bottom surface of the cavity C. The anodized layer 320may be formed on the entire or a part of the bottom surface of thecavity C.

A metal, for example aluminum, is connected to an anode and electrolyzedin a diluted acidic solution. Then, an oxide film, for example, aluminahaving a strong cohesive force with the metal is formed by oxygengenerated in the anode. This is different from electroplating in which ametal is connected to a cathode.

The heat sink 310 may include aluminum. In this case, the anodized layer320 may include alumina (Al₂O₃). However, the present invention is notlimited thereto, and metals such as copper, magnesium, titanium andtantalum may be used instead of aluminum. Generally, the anodized layerhas insulating properties, and alumina has superior electricalinsulating properties.

A metal layer pattern 330 is formed on the anodized layer 320. At leastone of the semiconductor chips 430, 440, 450 and/or 460 and a lead 470are mounted on the metal layer pattern 330 through the medium of thesolder paste layer (not shown).

The semiconductor chips 430, 440, 450 and/or 460 may include a powercontrol semiconductor chip and/or a low-power semiconductor chip drivingthe power control semiconductor chip. For example, the semiconductorchips 430, 440, 450 and/or 460 may include a silicon-controlledrectifier (SCR), a power transistor, an insulated-gate bipolartransistor (IGBT), a metal oxide semiconductor (MOS) transistor, a powerrectifier, a power regulator, an inverter, a converter, or a combinationthereof. The semiconductor chips 430, 440, 450 and/or 460 areelectrically connected to the metal layer pattern 330 by a bonding wire(not shown). Meanwhile, the anodized layer 320 insulates thesemiconductor chips 430, 440, 450 and/or 460 and the heat sink 310.

Although a dual in-line package (DIP) having two rows of leads 470 isexemplarily illustrated in FIG. 4, the scope of the present invention isnot limited to the structure of the lead 470. For example, a singlein-line package (SIP) having a single row of the lead 470 may beapplied.

The depth H of the cavity C of the heat sink 310 may be greater than thesum of a height of the anodized layer 320, a height of the metal layerpattern 330, a height of the semiconductor chips 430, 440, 450 and/or460. Here, the anodized layer 320, the metal layer pattern 330 and thesemiconductor chips 430, 440, 450 and/or 460 are arranged in the cavityC and do not protrude the upper surface of the heat sink 310.

Empty space of the cavity C may be filled with an epoxy resin 550 inorder to protect the anodized layer 320, the metal layer pattern 330 andthe semiconductor chips 430, 440, 450 and/or 460. The lead 470 mayextend from the metal layer pattern 330 outside of the epoxy resin 550.Thus, only a part of the lead 470 can be sealed with the epoxy resin550.

FIGS. 5A, 5C to 5E are cross-sectional view of the heat sink package ofFIG. 4, and FIG. 5B is a perspective view of the heat sink package ofFIG. 4 illustrating a method fabricating the heat sink package.

Referring to FIG. 5A, a heat sink 310 having a cavity C on an uppersurface thereof is prepared. An insulating anodized layer 320 is formedon the bottom surface of the cavity C. The anodized layer 320 may beformed on the entire or a part of bottom surface of the cavity C. Theheat sink 310 may include aluminum. In this case, the anodized layer 320may include alumina Al₂O₃). However, these materials forming the heatsink 310 and the anodized layer 320 are exemplarily described, and thescope of the present invention is not limited thereto. The metal layer330 a is formed on the anodized layer 320.

Referring to the cross-sectional view of the heat sink shown in FIG. 5Aand the perspective view of the heat sink shown in FIG. 5B, the cavity Chas a concave shape on the upper surface of the heat sink 310. However,the cavity is exemplarily illustrated. The cavity C may have anyconfiguration as long as the anodized layer 320, the metal layer pattern330 and the semiconductor chips 430, 440, 450 and/or 460 can be arrangedin the cavity C and do not protrude the upper surface of the heat sink310. For example, according to FIG. 5B, the cavity C in a lengthdirection of the heat sink 310 are closed by side walls and the cavityin a width direction of the heat sink 310 are open. However, all of theside walls of the cavity C may be closed according to anotherembodiment.

The depth H of the cavity C of the heat sink 310 may be greater than thesum of a height of the anodized layer 320, a height of the metal layerpattern 330, and a height of the semiconductor chips 430, 440, 450and/or 460.

Referring to FIG. 5C, the metal layer 330 a is patterned to form a metallayer pattern 330, and then a solder paste layer 340 is formed on themetal layer pattern 330. The solder paste layer 340 may be formed on themetal layer pattern 330 using dotting or screen printing.

Referring to FIG. 5D, at least one semiconductor chips 430, 440, 450and/or 460 and a lead 470 are mounted on the metal layer pattern 330.Although not shown in FIG. 5D, a solder paste layer may be interposedbetween the metal layer pattern 330 and the semiconductor chips 430,440, 450 and/or 460.

Referring to FIG. 5E, empty space of the cavity C may be filled with anepoxy resin 550 a in order to protect the anodized layer 320, the metallayer pattern 330 and the semiconductor chips 430, 440, 450 and/or 460.FIG. 5E illustrates a process of filling the cavity C with an epoxyresin 550 a. The epoxy resin 550 a may be filled in the cavity C using apotting method. After the cavity C is filled with the epoxy resin 550, acuring process is performed. Subsequently, electrical tests areperformed to determine the performance of products.

FIG. 6 is a cross-sectional view of a heat sink package according toanother embodiment of the present invention.

Referring to FIG, 6, a heat sink package includes a heat sink 610 havinga cavity on an upper surface thereof. A metal layer 620 is formed on thebottom surface of the cavity C. The metal layer 620 may be formed on theentire or a part of bottom surface of the cavity C.

The heat sink 610 may include aluminum. In this case, the metal layer620 may include copper. However, these materials forming the heat sink610 and the metal layer 620 are exemplarily described, and the scope ofthe present invention is not limited thereto. The copper layer may beformed, for example, by plating, but may also be formed by a chemicalvapor deposition.

A solder paste layer 630 is formed on the metal layer 620. Since thesolder paste layer 630 assembles the heat sink 610 and a semiconductorpackage, a bolt member which is conventionally required is notnecessary.

The semiconductor package may include a substrate 105; at least one ofsemiconductor chips 601 and 602 and a lead 607 mounted on the substrate105; and a molding member 608 sealing the semiconductor chips 601 and602 on the substrate 105. The molding member 608 may be formed to exposethe lower surface of the substrate 105 so that the substrate 105 can beattached to the solder paste layer 630. The molding member 608 may be anepoxy molding compound (EMC).

The substrate 105 may be a direct bonded copper (DBC) substrate, a thickor thin film copper (TFC) substrate or a direct fired copper (DFC)substrate. FIG. 6 illustrates a DBC substrate and a TFC substrate. TheDBC substrate and TFC substrate may include an insulating layer 102formed of an insulating material, for example, a ceramic material, anupper pattern 101 formed of copper and a lower pattern 103 formed ofcopper. The insulating layer 102 included in the substrate 105 insulatessemiconductor chips 601 and 602 and the heat sink 610.

The semiconductor chips 601 and 602 may include a power controlsemiconductor chip and/or a low-power semiconductor chip driving thepower control semiconductor chip. For example, the semiconductor chips601 and 602 may include a silicon-controlled rectifier (SCR), a powertransistor, an insulated-gate bipolar transistor (IGBT), a metal oxidesemiconductor (MOS) transistor, a power rectifier, a power regulator, aninverter, a converter or a combination thereof. The semiconductor chips601 and 602 are electrically connected to each other or to the substrate105 and/or lead 607 by a bonding wire 605.

Although a single in-line package (SIP) having a single row of the lead607 is exemplarily illustrated in FIG. 6, the scope of the presentinvention is not limited to the structure of the lead 607. For example,a dual in-line package (DIP) having two rows of leads 607 may beapplied. The lead 607 is attached to the substrate 105 and extendsoutside of the molding member 608.

A lower portion of the semiconductor package including the substrate105, the semiconductor chips 601 and 602 and the molding member 608 isdisposed in the cavity C of the heat sink 610, and an upper portion ofthe semiconductor package may protrude the upper surface of the heatsink 610. However, the configuration of the semiconductor package isexemplarily illustrated herein, and the scope of the present inventionis not limited thereto. For example, the semiconductor package may bedisposed in the cavity C such that the upper portion of thesemiconductor package does not protrude the upper surface of the heatsink 610. Empty space which is not occupied by the semiconductor packagein the cavity C may be filled with an epoxy resin.

FIGS. 7A to 7C are cross-sectional views of the heat sink package ofFIG. 6 illustrating a method fabricating the heat sink package.

Referring to FIG. 7A, a semiconductor package 600 includes a substrate105; at least one semiconductor chips 601 and 602 and a lead 607 formedon the substrate 105; and a molding member 608 sealing the semiconductorchips 601 and 602 on the substrate 105.

The substrate 105 may be a direct bonded copper (DBC) substrate, a thickor thin film copper (TFC) substrate or a direct fired copper (DFC)substrate. FIG. 7A illustrates a DBC substrate or TFC substrate. The DBCsubstrate and TFC substrate may include an insulating layer 102 formedof an insulating material, for example, a ceramic material, an upperpattern 101 formed of copper and a lower pattern 103 formed of copper.The semiconductor chips 601 and 602 and the lead 607 may be mounted onthe upper pattern 101 of the substrate 105. The lead 607 extends outsideof the molding member 608.

Referring to FIG. 78, a heat sink 610 having a cavity C on an uppersurface thereof is prepared. A metal layer 620 is formed on the bottomsurface of the cavity C. The metal layer 620 may be formed on the entireor a part of bottom surface of the cavity C. The heat sink 610 mayinclude aluminum. In this case, the metal layer 620 may include copper.However, these materials forming the heat sink 610 and the metal layer620 are exemplarily described, and the scope of the present invention isnot limited thereto. The copper layer may be formed, for example, byplating, but may also be formed by a chemical vapor deposition.

After the metal layer 620 is formed, a solder paste layer 630 is formedon the metal layer 620 to form a heat sink structure 650. The solderpaste layer 630 may be formed on the metal layer 620 using a dotting orscreen printing method.

Referring to FIG. 7C, the semiconductor package 600 is mounted on theheat sink structure 650 to prepare the heat sink package. That is, sincethe substrate of the semiconductor package 600 is attached to the solderpaste layer of the heat sink structure 650, a bolt member which isconventionally required is not necessary. Subsequently, electrical testsare performed to determine the performance of products.

FIG. 8 is a cross-sectional view of a heat sink package according toanother embodiment of the present invention.

Referring to FIG, 8, a heat sink package includes a heat sink 710 nothaving a cavity on an upper surface thereof. A metal layer 720 is formedon an upper surface of the heat sink 710.

The heat sink 710 may include aluminum. In this case, the metal layer720 may include copper. However, these materials forming the heat sink710 and the metal layer 720 are exemplarily described, and the scope ofthe present invention is not limited thereto. The copper layer may beformed, for example, by plating, but may also be formed by a chemicalvapor deposition.

A solder paste layer 730 is formed on the metal layer 720. Since thesolder paste layer 730 assembles the heat sink 710 and a semiconductorpackage, a bolt member which is conventionally required is notnecessary.

The semiconductor package may include a substrate 105; at least one ofsemiconductor chips 601 and 602 and a lead 607 mounted on the substrate105; and a molding member 608 sealing the semiconductor chips 601 and602 on the substrate 105 The semiconductor package illustrated in FIG, 8is the same as that of FIG. 6.

FIGS. 9A, 9B and 9C are cross-sectional views of the heat sink packageof FIG. 8, and FIG. 9C is a perspective view of the heat sink package ofFIG. 8 illustrating a method fabricating the heat sink package.

Referring to FIG. 9A, the semiconductor package 600 includes a substrate105; at least one of semiconductor chips 601 and 602 and a lead 607mounted on the substrate 105 and a molding member 608 sealing thesemiconductor chips 601 and 602 on the substrate 105. The semiconductorpackage 600 is described with reference to FIG. 7A, and will not bepresent herein.

Referring to FIG. 9B and 9C, a heat sink 710 not having a cavity on anupper surface thereof is prepared. A metal layer 720 is formed on anupper surface of the heat sink 710. The heat sink 710 may includealuminum. In this case, the metal layer 720 may include copper. However,these materials forming the heat sink 710 and the metal layer 720 areexemplarily described, and the scope of the present invention is notlimited thereto. The copper layer may be formed, for example, byplating, but may also be formed by a chemical vapor deposition.

The solder paste layer 730 is formed on the metal layer 720 to form aheat sink structure 700. The solder paste layer 730 may be formed on themetal layer 720 using a dotting or screen printing method. Since thesolder paste layer 730 assembles the heat sink 710 and the substrate105, a bolt member which is conventionally required is not necessary.

Referring to the cross-sectional view of the heat sink shown in FIG. 9Band the perspective view of the heat sink shown in FIG. 9C, a groove isformed on the upper surface of the heat sink 710. The groove G is formedin order to prevent overflow of the solder paste layer 730 when thesolder paste layer 730 is formed.

Referring to FIG. 9C, the groove G is disposed in parallel to the widthdirection of the heat sink 710. However, the groove G is exemplarilyillustrated. The groove G may be formed in any way as long as it canprevent overflow of the solder paste layer 730 in subsequent processes.For example, a groove G may further be disposed in parallel to thelength direction of the heat sink 710 around the solder paste layer 730.

Referring to FIG. 9D, the semiconductor package 600 is mounted on theheat sink structure 700 to prepare the heat sink package. That is, sincethe substrate of the semiconductor package 600 is attached to the solderpaste layer of the heat sink structure 700, a bolt member which isconventionally required is not necessary. Subsequently, electrical testsare performed to determine the performance of products.

In the heat sink package according to the present invention, thesemiconductor package and the heat sink can be bound to each other inorder to prevent cracks and warpages and secure low thermal resistance.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A heat sink package comprising: a heat sinkhaving a cavity on an upper surface thereof: a metal layer formed on thebottom surface of the cavity; a solder paste layer formed on the metallayer; and a semiconductor package on the solder paste layer.
 2. Theheat sink package of claim 1, wherein the heat sink comprises aluminumand the metal layer comprises copper.
 3. The heat sink package of claim1, wherein the semiconductor package comprises: a substrate; a lead anda semiconductor chip on the substrate and a molding member sealing thesemiconductor chip on the substrate.
 4. The heat sink package of claim1, wherein the substrate is selected from the group consisting of adirect bonded copper (OBC) substrate, a thick or thin film copper (TFC)substrate and a direct fired copper (OFC) substrate.
 5. The heat sinkpackage of claim 1, wherein the lead extends from the substrate towardthe outside of the molding member.
 6. A heat sink package comprising: aheat sink; a metal layer formed on the heat sink; a solder paste layerformed on the metal layer; and a semiconductor package on the solderpaste layer.
 7. The heat sink package of claim 6, wherein a groove isformed on the upper surface of the heat sink around the solder pastelayer in order to prevent overflow of the solder paste layer.
 8. Theheat sink package of claim 6, wherein the semiconductor packagecomprises: a substrate; a lead and a semiconductor chip on the substrateand a molding member sealing the semiconductor chip on the substrate. 9.The heat sink package of claim 8, wherein the substrate is selected fromthe group consisting of a direct bonded copper (DBC) substrate, a thickor thin film copper (TFC) substrate and a direct fired copper (DFC)substrate.
 10. The heat sink package of claim 8, wherein the leadextends from the substrate outside of the molding member.